Now that you have your 3D printer, you want to print everything under the sun. However, printing can be very time consuming. But there are a few ways to increase your 3D printing speed.
The best source of increased printing speed is the nozzle. Replace the nozzle with a larger nozzle. If you are not concerned about fine detail, you can set the nozzle diameter as larger than it is in your slicer, a technique called nozzle overloading. After that, tweak your printer speed settings.
Picking the right nozzle size and nozzle overloading are not difficult. These techniques are the first steps to speeding up printing, more so than increasing print speeds.
Caveats To Faster Printing
There are multiple factors to take into account regardless of which method you use to increase your print speed.
When you print faster, your printer has to push more filament out. This is true whether you increase the nozzle size or increase the print speed.
To push more filament out, the extruder has to push filament through the hotend faster. But filament needs time to melt before it can be extruded.
Most printers use 1.75 mm thickness filament. Thinner filament means that even more filament has to be pushed into the hotend to get the same amount of plastic out.
You might think using the 2.85 mm filament to get more filament in the hotend would reduce this problem. This thicker filament introduces a new problem.
Using a thicker filament, the heat from the hotend needs to penetrate further into the filament to complete melt it. 2.85 mm used to be the filament standard. However, because it actually takes so long to melt through it was replaced by 1.75 mm filament.
Since we need to melt filament faster if we want to increase our print speed, we will need to increase our print temperatures. This means printing at the higher end of the temperature range.
We still have to be careful not to print too high. A very high print temperature will cause the filament to burn. For the most part, while the filament is being extruded, we can push filament out fast enough that is doesn’t have a chance to burn. But when the printer stops extruding, either to move between parts or change layers, filament burning becomes a potential problem.
When you burn the filament, the burnt pieces can clog nozzle or cause serious print defects. It is best to try to avoid burning the filament as much as possible.
Another caveat to be aware of is that printing faster means reduced quality. No matter how you do it, every technique to increase print speed requires sacrificing some level of print quality.
Picking The Nozzle Size
The larger the nozzle size, the lower the resolution in the X-Y. Small features when you look down on the print cannot be smaller that the nozzle diameter if they are to successfully print.
The features of your print will limit the nozzle size you will want to pick.
That being said, the most effective way to increase print speed is to increase the nozzle size. The larger the nozzle opening, the fewer lines need to be drawn on each layer.
All of my printers came with 0.4 mm nozzles. This is the standard nozzle size for FDM printers.
I recommend this set of tungsten nozzles on Amazon. Since we will be printing at higher temperatures, the extra heat resistance will prevent the nozzle from wearing out.
For maximum speed, you can use the 1 mm nozzle. However, before trying to print with such a large nozzle, consider the the features of your print.
The biggest reason to print faster is because you have a large object that will take a long time to print. These objects usually do not have high detailed small features. But you will want to examine the model carefully for any spots that may be too thin to print at 1 mm.
An advantage of a larger nozzle is that you can also increase the layer height. The rule of thumb with layer height is that your layers should be no more than 80% of the nozzle diameter.
So for a standard 0.4 mm nozzle, you should not exceed 0.32 mm layer heights. With a 1.0 mm nozzle, you can print with a layer height up to 0.8 mm.
Layer heights distort features along the z-axis. As with the nozzle size, you will want to be careful trying to print finer details when you use large layer heights.
Your printer does not know what size of nozzle you have installed. If you lie to it and tell it you installed a larger nozzle, the printer is happy to go on its way printing like you have the larger nozzle.
In fact for the most part, the printer will successfully print just as if it actually had the larger nozzle.
If you have a nozzle with an opening of 0.4 mm, the entire end of the nozzle will be considerably larger than 0.4 mm. As long as the end of the nozzle is wide enough to keep the extruded filament pushed down, you can successfully print as if you had a larger nozzle.
Here is how it works. Say you set the nozzle diameter to 0.5 mm even though you have a 0.4 mm nozzle. The printer will think that you have the 0.5 mm nozzle and attempt to extrude enough plastic to draw 0.5 mm thick lines.
Since you only have a 0.4 mm nozzle, there is too much plastic extruding from the nozzle. This extra plastic is forced to the sides and kept down by the nozzle end.
In the end, you are effectively able to print as if you had the larger nozzle size, gaining all the print speed advantages.
Overloading the nozzle will reduce the print quality. When you push extra plastic, it will not exactly flow out perfectly evenly to both sides of the opening. But the drop in quality is not significant if you do not overload too much.
How much can you overload your nozzle?
The rule of thumb is overload by no more than 50% of the true nozzle opening diameter. This means that for the standard 0.4 mm nozzle, set the nozzle size to no more than 0.6 mm. By keeping the overloading low, you ensure the nozzle will be able to press the filament down completely.
Layer height rules apply here as well. With a 0.4 mm nozzle, you should set a layer height of no more than 0.32 mm. With the nozzle overloaded to 0.6 mm, the maximum layer height you would want to use is 0.48 mm. Just remember, your mileage may vary.
Why Not Just Increase Print Speeds?
Here is the question everyone asks. Since we want to print faster, why not just increase print speeds?
There are several factors that make increasing print speeds less effective at increasing printing speed.
The motors have acceleration limits. Your print head cannot go from 0 to 30 mm/second in an instant, it takes time to speed up. If you try to increase acceleration, you risk the belt slipping causing a print failure.
Faster print speeds also introduce more vibrations in the machine. Small gains in speed can have drastic effects on print quality.
Additionally, faster print speeds can result in sub-optimal extrusion. The print head is just moving too fast to lay down good layers.
Some of these settings can be improved. Just remember, the gains from increasing speed tend to be small compared to the subsequent loss in print quality.
First, properly tune your acceleration. This is an advanced procedure and does require you to access your printer through a terminal such as OctoPrint. The steps required for acceleration tuning can be found here.
Because faster print speeds can lead to vibrations, you can print vibration damping supports for your printer. You can find these prints over on Thingiverse.
To tune your print speed, print out a benchy model at various print speeds. Notice the quality changes as the speed increases. Increase in 5-10 mm/second increments. Until the quality drops too low.
You may find that you cannot increase the speed very far without seeing severe quality decreases. This is because you tend to print near the upper limit of your speed range and there isn’t much more that you can pull out.
Be careful trying to combine this technique with the other techniques. You may find that with larger nozzles or nozzle overloading, increase the speed causes print quality to drop a lot faster than it does when printing standard nozzles with no overloading.